The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Philippe De Lajudie - One of the best experts on this subject based on the ideXlab platform.
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methylobacterium nodulans sp nov for a group of aerobic facultatively methylotrophic legume Root Nodule forming and nitrogen fixing bacteria
International Journal of Systematic and Evolutionary Microbiology, 2004Co-Authors: Philippe Jourand, Eric Giraud, Anne Willems, Monique Gillis, Gilles Bena, Bernard Dreyfus, Philippe De LajudieAbstract:Data on 72 non-pigmented bacterial strains that specifically induce nitrogen-fixing Root Nodules on the legume species Crotalaria glaucoides, Crotalaria perrottetii and Crotalaria podocarpa are reviewed. By SDS-PAGE analysis of total protein patterns and by 16S rRNA PCR-RFLP, these strains form a homogeneous group that is separate from other legume Root-Nodule-forming bacteria. The 16S rRNA gene-based phylogeny indicates that these bacteria belong to the genus Methylobacterium. They can grow on C1 compounds such as methanol, formate and formaldehyde but not methylamine as sole carbon source, and carry an mxaF gene, encoding methanol dehydrogenase, which supports their methylotrophic metabolism. Presence of a nodA nodulation gene, and ability to nodulate plants of Crotalaria species and to fix nitrogen are features that separate the strains currently included in this group from other members of the genus Methylobacterium. The present study includes additional genotypic and phenotypic characterization of this novel Methylobacterium species, i.e. nifH gene sequence, morphology, physiology, enzymic and carbon source assimilation tests and antibiotic resistance. The name Methylobacterium nodulans sp. nov. (type strain, ORS 2060T=CNCM I 2342T=LMG 21967T) is proposed for this group of Root-Nodule-forming bacteria.
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methylobacterium nodulans sp nov for a group of aerobic facultatively methylotrophic legume Root Nodule forming and nitrogen fixing bacteria
International Journal of Systematic and Evolutionary Microbiology, 2004Co-Authors: Philippe Jourand, Eric Giraud, Anne Willems, Monique Gillis, Gilles Bena, Bernard Dreyfus, Abdoulaye Sy, Philippe De LajudieAbstract:Data on 72 non-pigmented bacterial strains that specifically induce nitrogen-fixing Root Nodules on the legume species Crotalaria glaucoides, Crotalaria perrottetii and Crotalaria podocarpa are reviewed. By SDS-PAGE analysis of total protein patterns and by 16S rRNA PCR-RFLP, these strains form a homogeneous group that is separate from other legume Root-Nodule-forming bacteria. The 16S rRNA gene-based phylogeny indicates that these bacteria belong to the genus Methylobacterium. They can grow on C1 compounds such as methanol, formate and formaldehyde but not methylamine as sole carbon source, and carry an mxaF gene, encoding methanol dehydrogenase, which supports their methylotrophic metabolism. Presence of a nodA nodulation gene, and ability to nodulate plants of Crotalaria species and to fix nitrogen are features that separate the strains currently included in this group from other members of the genus Methylobacterium. The present study includes additional genotypic and phenotypic characterization of this novel Methylobacterium species, i.e. nifH gene sequence, morphology, physiology, enzymic and carbon source assimilation tests and antibiotic resistance. The name Methylobacterium nodulans sp. nov. (type strain, ORS 2060T=CNCM I 2342T=LMG 21967T) is proposed for this group of Root-Nodule-forming bacteria.
Masayoshi Kawaguchi - One of the best experts on this subject based on the ideXlab platform.
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Reactive Sulfur Species Interact with Other Signal Molecules in Root Nodule Symbiosis in Lotus japonicus.
Antioxidants (Basel Switzerland), 2020Co-Authors: Mitsutaka Fukudome, Hazuki Shimada, Nahoko Uchi, Ken-ichi Osuki, Haruka Ishizaki, Ei-ichi Murakami, Masayoshi Kawaguchi, Toshiki UchiumiAbstract:Reactive sulfur species (RSS) function as strong antioxidants and are involved in various biological responses in animals and bacteria. Few studies; however, have examined RSS in plants. In the present study, we clarified that RSS are involved in Root Nodule symbiosis in the model legume Lotus japonicus. Polysulfides, a type of RSS, were detected in the Roots by using a sulfane sulfur-specific fluorescent probe, SSP4. Supplying the sulfane sulfur donor Na2S3 to the Roots increased the amounts of both polysulfides and hydrogen sulfide (H2S) in the Roots and simultaneously decreased the amounts of nitric oxide (NO) and reactive oxygen species (ROS). RSS were also detected in infection threads in the Root hairs and in infected cells of Nodules. Supplying the sulfane sulfur donor significantly increased the numbers of infection threads and Nodules. When Nodules were immersed in the sulfane sulfur donor, their nitrogenase activity was significantly reduced, without significant changes in the amounts of NO, ROS, and H2S. These results suggest that polysulfides interact with signal molecules such as NO, ROS, and H2S in Root Nodule symbiosis in L. japonicus. SSP4 and Na2S3 are useful tools for study of RSS in plants.
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a shared gene drives lateral Root development and Root Nodule symbiosis pathways in lotus
Science, 2019Co-Authors: Masayoshi Kawaguchi, Takashi Soyano, Yoshikazu Shimoda, Makoto HayashiAbstract:Legumes develop Root Nodules in symbiosis with nitrogen-fixing rhizobial bacteria. Rhizobia evoke cell division of differentiated cortical cells into Root Nodule primordia for accommodating bacterial symbionts. In this study, we show that Nodule INCEPTION (NIN), a transcription factor in Lotus japonicus that is essential for initiating cortical cell divisions during nodulation, regulates the gene ASYMMETRIC LEAVES 2-LIKE18/LATERAL ORGAN BOUNDARIES DOMAIN16a (ASL18/LBD16a). Orthologs of ASL18/LBD16a in nonlegume plants are required for lateral Root development. Coexpression of ASL18a and the CCAAT box–binding protein Nuclear Factor-Y (NF-Y) subunits, which are also directly targeted by NIN, partially suppressed the nodulation-defective phenotype of L. japonicusdaphne mutants, in which cortical expression of NIN was attenuated. Our results demonstrate that ASL18a and NF-Y together regulate Nodule organogenesis. Thus, a lateral Root developmental pathway is incorporated downstream of NIN to drive Nodule symbiosis.
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LACK OF SYMBIONT ACCOMMODATION controls intracellular symbiont accommodation in Root Nodule and arbuscular mycorrhizal symbiosis in Lotus japonicus.
Public Library of Science (PLoS), 2019Co-Authors: Takuya Suzaki, Hanna Nishida, Momoyo Ito, Naoya Takeda, Motomi Hoshino, Fumika Misawa, Yoshihiro Handa, Kenji Miura, Masayoshi KawaguchiAbstract:Nitrogen-fixing rhizobia and arbuscular mycorrhizal fungi (AMF) form symbioses with plant Roots and these are established by precise regulation of symbiont accommodation within host plant cells. In model legumes such as Lotus japonicus and Medicago truncatula, rhizobia enter into Roots through an intracellular invasion system that depends on the formation of a Root-hair infection thread (IT). While IT-mediated intracellular rhizobia invasion is thought to be the most evolutionarily derived invasion system, some studies have indicated that a basal intercellular invasion system can replace it when some nodulation-related factors are genetically modified. In addition, intracellular rhizobia accommodation is suggested to have a similar mechanism as AMF accommodation. Nevertheless, our understanding of the underlying genetic mechanisms is incomplete. Here we identify a L. japonicus nodulation-deficient mutant, with a mutation in the LACK OF SYMBIONT ACCOMMODATION (LAN) gene, in which Root-hair IT formation is strongly reduced, but intercellular rhizobial invasion eventually results in functional Nodule formation. LjLAN encodes a protein that is homologous to Arabidopsis MEDIATOR 2/29/32 possibly acting as a subunit of a Mediator complex, a multiprotein complex required for gene transcription. We also show that LjLAN acts in parallel with a signaling pathway including LjCYCLOPS. In addition, the lan mutation drastically reduces the colonization levels of AMF. Taken together, our data provide a new factor that has a common role in symbiont accommodation process during Root Nodule and AM symbiosis
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genetic basis of cytokinin and auxin functions during Root Nodule development
Frontiers in Plant Science, 2013Co-Authors: Masayoshi Kawaguchi, Takuya Suzaki, Momoyo ItoAbstract:The phytohormones cytokinin and auxin are essential for the control of diverse aspects of cell proliferation and differentiation processes in plants. Although both phytohormones have been suggested to play key roles in the regulation of Root Nodule development, only recently, significant progress has been made in the elucidation of the molecular genetic basis of cytokinin action in the model leguminous species, Lotus japonicus and Medicago truncatula. Identification and functional analyses of the putative cytokinin receptors LOTUS HISTIDINE KINASE 1 and M. truncatula CYTOKININ RESPONSE 1 have brought a greater understanding of how activation of cytokinin signaling is crucial to the initiation of Nodule primordia. Recent studies have also started to shed light on the roles of auxin in the regulation of Nodule development. Here, we review the history and recent progress of research into the roles of cytokinin and auxin, and their possible interactions, in Nodule development.
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positive and negative regulation of cortical cell division during Root Nodule development in lotus japonicus is accompanied by auxin response
Development, 2012Co-Authors: Masayoshi Kawaguchi, Takuya Suzaki, Momoyo Ito, Yosuke Umehara, Koji Yano, Norio SuganumaAbstract:Nodulation is a form of de novo organogenesis that occurs mainly in legumes. During early Nodule development, the host plant Root is infected by rhizobia that induce dedifferentiation of some cortical cells, which then proliferate to form the symbiotic Root Nodule primordium. Two classic phytohormones, cytokinin and auxin, play essential roles in diverse aspects of cell proliferation and differentiation. Although recent genetic studies have established how activation of cytokinin signaling is crucial to the control of cortical cell differentiation, the physiological pathways through which auxin might act in Nodule development are poorly characterized. Here, we report the detailed patterns of auxin accumulation during Nodule development in Lotus japonicus. Our analyses showed that auxin predominantly accumulates in dividing cortical cells and that Nodule INCEPTION, a key transcription factor in Nodule development, positively regulates this accumulation. Additionally, we found that auxin accumulation is inhibited by a systemic negative regulatory mechanism termed autoregulation of nodulation (AON). Analysis of the constitutive activation of LjCLE-RS genes, which encode putative Root-derived signals that function in AON, in combination with the determination of auxin accumulation patterns in proliferating cortical cells, indicated that activation of LjCLE-RS genes blocks the progress of further cortical cell division, probably through controlling auxin accumulation. Our data provide evidence for the existence of a novel fine-tuning mechanism that controls Nodule development in a cortical cell stage-dependent manner.
Monique Gillis - One of the best experts on this subject based on the ideXlab platform.
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methylobacterium nodulans sp nov for a group of aerobic facultatively methylotrophic legume Root Nodule forming and nitrogen fixing bacteria
International Journal of Systematic and Evolutionary Microbiology, 2004Co-Authors: Philippe Jourand, Eric Giraud, Anne Willems, Monique Gillis, Gilles Bena, Bernard Dreyfus, Philippe De LajudieAbstract:Data on 72 non-pigmented bacterial strains that specifically induce nitrogen-fixing Root Nodules on the legume species Crotalaria glaucoides, Crotalaria perrottetii and Crotalaria podocarpa are reviewed. By SDS-PAGE analysis of total protein patterns and by 16S rRNA PCR-RFLP, these strains form a homogeneous group that is separate from other legume Root-Nodule-forming bacteria. The 16S rRNA gene-based phylogeny indicates that these bacteria belong to the genus Methylobacterium. They can grow on C1 compounds such as methanol, formate and formaldehyde but not methylamine as sole carbon source, and carry an mxaF gene, encoding methanol dehydrogenase, which supports their methylotrophic metabolism. Presence of a nodA nodulation gene, and ability to nodulate plants of Crotalaria species and to fix nitrogen are features that separate the strains currently included in this group from other members of the genus Methylobacterium. The present study includes additional genotypic and phenotypic characterization of this novel Methylobacterium species, i.e. nifH gene sequence, morphology, physiology, enzymic and carbon source assimilation tests and antibiotic resistance. The name Methylobacterium nodulans sp. nov. (type strain, ORS 2060T=CNCM I 2342T=LMG 21967T) is proposed for this group of Root-Nodule-forming bacteria.
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methylobacterium nodulans sp nov for a group of aerobic facultatively methylotrophic legume Root Nodule forming and nitrogen fixing bacteria
International Journal of Systematic and Evolutionary Microbiology, 2004Co-Authors: Philippe Jourand, Eric Giraud, Anne Willems, Monique Gillis, Gilles Bena, Bernard Dreyfus, Abdoulaye Sy, Philippe De LajudieAbstract:Data on 72 non-pigmented bacterial strains that specifically induce nitrogen-fixing Root Nodules on the legume species Crotalaria glaucoides, Crotalaria perrottetii and Crotalaria podocarpa are reviewed. By SDS-PAGE analysis of total protein patterns and by 16S rRNA PCR-RFLP, these strains form a homogeneous group that is separate from other legume Root-Nodule-forming bacteria. The 16S rRNA gene-based phylogeny indicates that these bacteria belong to the genus Methylobacterium. They can grow on C1 compounds such as methanol, formate and formaldehyde but not methylamine as sole carbon source, and carry an mxaF gene, encoding methanol dehydrogenase, which supports their methylotrophic metabolism. Presence of a nodA nodulation gene, and ability to nodulate plants of Crotalaria species and to fix nitrogen are features that separate the strains currently included in this group from other members of the genus Methylobacterium. The present study includes additional genotypic and phenotypic characterization of this novel Methylobacterium species, i.e. nifH gene sequence, morphology, physiology, enzymic and carbon source assimilation tests and antibiotic resistance. The name Methylobacterium nodulans sp. nov. (type strain, ORS 2060T=CNCM I 2342T=LMG 21967T) is proposed for this group of Root-Nodule-forming bacteria.
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a new species of devosia that forms a unique nitrogen fixing Root Nodule symbiosis with the aquatic legume neptunia natans l f druce
Applied and Environmental Microbiology, 2002Co-Authors: Raul Rivas, Encarna Velázquez, Anne Willems, Monique Gillis, Nieves Vizcaino, Nanjappa S Subbarao, Pedro F Mateos, Frank B Dazzo, Eustoquio MartinezmolinaAbstract:Rhizobia are the common bacterial symbionts that form nitrogen-fixing Root Nodules in legumes. However, recently other bacteria have been shown to nodulate and fix nitrogen symbiotically with these plants. Neptunia natans is an aquatic legume indigenous to tropical and subtropical regions and in African soils is nodulated by Allorhizobium undicola. This legume develops an unusual Root-Nodule symbiosis on floating stems in aquatic environments through a unique infection process. Here, we analyzed the low-molecular-weight RNA and 16S ribosomal DNA (rDNA) sequence of the same fast-growing isolates from India that were previously used to define the developmental morphology of the unique infection process in this symbiosis with N. natans and found that they are phylogenetically located in the genus Devosia, not Allorhizobium or Rhizobium. The 16S rDNA sequences of these two Neptunia-nodulating Devosia strains differ from the only species currently described in that genus, Devosia riboflavina. From the same isolated colonies, we also located their nodD and nifH genes involved in nodulation and nitrogen fixation on a plasmid of approximately 170 kb. Sequence analysis showed that their nodD and nifH genes are most closely related to nodD and nifH of Rhizobium tropici, suggesting that this newly described Neptunia-nodulating Devosia species may have acquired these symbiotic genes by horizontal transfer.
Anne Willems - One of the best experts on this subject based on the ideXlab platform.
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methylobacterium nodulans sp nov for a group of aerobic facultatively methylotrophic legume Root Nodule forming and nitrogen fixing bacteria
International Journal of Systematic and Evolutionary Microbiology, 2004Co-Authors: Philippe Jourand, Eric Giraud, Anne Willems, Monique Gillis, Gilles Bena, Bernard Dreyfus, Philippe De LajudieAbstract:Data on 72 non-pigmented bacterial strains that specifically induce nitrogen-fixing Root Nodules on the legume species Crotalaria glaucoides, Crotalaria perrottetii and Crotalaria podocarpa are reviewed. By SDS-PAGE analysis of total protein patterns and by 16S rRNA PCR-RFLP, these strains form a homogeneous group that is separate from other legume Root-Nodule-forming bacteria. The 16S rRNA gene-based phylogeny indicates that these bacteria belong to the genus Methylobacterium. They can grow on C1 compounds such as methanol, formate and formaldehyde but not methylamine as sole carbon source, and carry an mxaF gene, encoding methanol dehydrogenase, which supports their methylotrophic metabolism. Presence of a nodA nodulation gene, and ability to nodulate plants of Crotalaria species and to fix nitrogen are features that separate the strains currently included in this group from other members of the genus Methylobacterium. The present study includes additional genotypic and phenotypic characterization of this novel Methylobacterium species, i.e. nifH gene sequence, morphology, physiology, enzymic and carbon source assimilation tests and antibiotic resistance. The name Methylobacterium nodulans sp. nov. (type strain, ORS 2060T=CNCM I 2342T=LMG 21967T) is proposed for this group of Root-Nodule-forming bacteria.
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methylobacterium nodulans sp nov for a group of aerobic facultatively methylotrophic legume Root Nodule forming and nitrogen fixing bacteria
International Journal of Systematic and Evolutionary Microbiology, 2004Co-Authors: Philippe Jourand, Eric Giraud, Anne Willems, Monique Gillis, Gilles Bena, Bernard Dreyfus, Abdoulaye Sy, Philippe De LajudieAbstract:Data on 72 non-pigmented bacterial strains that specifically induce nitrogen-fixing Root Nodules on the legume species Crotalaria glaucoides, Crotalaria perrottetii and Crotalaria podocarpa are reviewed. By SDS-PAGE analysis of total protein patterns and by 16S rRNA PCR-RFLP, these strains form a homogeneous group that is separate from other legume Root-Nodule-forming bacteria. The 16S rRNA gene-based phylogeny indicates that these bacteria belong to the genus Methylobacterium. They can grow on C1 compounds such as methanol, formate and formaldehyde but not methylamine as sole carbon source, and carry an mxaF gene, encoding methanol dehydrogenase, which supports their methylotrophic metabolism. Presence of a nodA nodulation gene, and ability to nodulate plants of Crotalaria species and to fix nitrogen are features that separate the strains currently included in this group from other members of the genus Methylobacterium. The present study includes additional genotypic and phenotypic characterization of this novel Methylobacterium species, i.e. nifH gene sequence, morphology, physiology, enzymic and carbon source assimilation tests and antibiotic resistance. The name Methylobacterium nodulans sp. nov. (type strain, ORS 2060T=CNCM I 2342T=LMG 21967T) is proposed for this group of Root-Nodule-forming bacteria.
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a new species of devosia that forms a unique nitrogen fixing Root Nodule symbiosis with the aquatic legume neptunia natans l f druce
Applied and Environmental Microbiology, 2002Co-Authors: Raul Rivas, Encarna Velázquez, Anne Willems, Monique Gillis, Nieves Vizcaino, Nanjappa S Subbarao, Pedro F Mateos, Frank B Dazzo, Eustoquio MartinezmolinaAbstract:Rhizobia are the common bacterial symbionts that form nitrogen-fixing Root Nodules in legumes. However, recently other bacteria have been shown to nodulate and fix nitrogen symbiotically with these plants. Neptunia natans is an aquatic legume indigenous to tropical and subtropical regions and in African soils is nodulated by Allorhizobium undicola. This legume develops an unusual Root-Nodule symbiosis on floating stems in aquatic environments through a unique infection process. Here, we analyzed the low-molecular-weight RNA and 16S ribosomal DNA (rDNA) sequence of the same fast-growing isolates from India that were previously used to define the developmental morphology of the unique infection process in this symbiosis with N. natans and found that they are phylogenetically located in the genus Devosia, not Allorhizobium or Rhizobium. The 16S rDNA sequences of these two Neptunia-nodulating Devosia strains differ from the only species currently described in that genus, Devosia riboflavina. From the same isolated colonies, we also located their nodD and nifH genes involved in nodulation and nitrogen fixation on a plasmid of approximately 170 kb. Sequence analysis showed that their nodD and nifH genes are most closely related to nodD and nifH of Rhizobium tropici, suggesting that this newly described Neptunia-nodulating Devosia species may have acquired these symbiotic genes by horizontal transfer.
Takuya Suzaki - One of the best experts on this subject based on the ideXlab platform.
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LACK OF SYMBIONT ACCOMMODATION controls intracellular symbiont accommodation in Root Nodule and arbuscular mycorrhizal symbiosis in Lotus japonius
Public Library of Science, 2019Co-Authors: 壽崎 拓哉, Hanna Nishida, Takuya Suzaki, Momoyo Ito, 三浦 謙治, Naoya Takeda, Motomi Hoshino, Fumika Misawa, Yoshihiro Handa, Kenji MiuraAbstract:Nitrogen-fixing rhizobia and arbuscular mycorrhizal fungi (AMF) form symbioses with plant Roots and these are established by precise regulation of symbiont accommodation within host plant cells. In model legumes such as Lotus japonicus and Medicago truncatula, rhizobia enter into Roots through an intracellular invasion system that depends on the formation of a Root-hair infection thread (IT). While IT-mediated intracellular rhizobia invasion is thought to be the most evolutionarily derived invasion system, some studies have indicated that a basal intercellular invasion system can replace it when some nodulation-related factors are genetically modified. In addition, intracellular rhizobia accommodation is suggested to have a similar mechanism as AMF accommodation. Nevertheless, our understanding of the underlying genetic mechanisms is incomplete. Here we identify a L. japonicus nodulation-deficient mutant, with a mutation in the LACK OF SYMBIONT ACCOMMODATION (LAN) gene, in which Root-hair IT formation is strongly reduced, but intercellular rhizobial invasion eventually results in functional Nodule formation. LjLAN encodes a protein that is homologous to Arabidopsis MEDIATOR 2/29/32 possibly acting as a subunit of a Mediator complex, a multiprotein complex required for gene transcription. We also show that LjLAN acts in parallel with a signaling pathway including LjCYCLOPS. In addition, the lan mutation drastically reduces the colonization levels of AMF. Taken together, our data provide a new factor that has a common role in symbiont accommodation process during Root Nodule and AM symbiosis.Correction: LACK OF SYMBIONT ACCOMMODATION controls intracellular symbiont accommodation in Root Nodule and arbuscular mycorrhizal symbiosis in Lotus japonicus. PLoS Genet 15(1): e1007966. https://doi.org/10.1371/journal.pgen.100796
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LACK OF SYMBIONT ACCOMMODATION controls intracellular symbiont accommodation in Root Nodule and arbuscular mycorrhizal symbiosis in Lotus japonicus.
Public Library of Science (PLoS), 2019Co-Authors: Takuya Suzaki, Hanna Nishida, Momoyo Ito, Naoya Takeda, Motomi Hoshino, Fumika Misawa, Yoshihiro Handa, Kenji Miura, Masayoshi KawaguchiAbstract:Nitrogen-fixing rhizobia and arbuscular mycorrhizal fungi (AMF) form symbioses with plant Roots and these are established by precise regulation of symbiont accommodation within host plant cells. In model legumes such as Lotus japonicus and Medicago truncatula, rhizobia enter into Roots through an intracellular invasion system that depends on the formation of a Root-hair infection thread (IT). While IT-mediated intracellular rhizobia invasion is thought to be the most evolutionarily derived invasion system, some studies have indicated that a basal intercellular invasion system can replace it when some nodulation-related factors are genetically modified. In addition, intracellular rhizobia accommodation is suggested to have a similar mechanism as AMF accommodation. Nevertheless, our understanding of the underlying genetic mechanisms is incomplete. Here we identify a L. japonicus nodulation-deficient mutant, with a mutation in the LACK OF SYMBIONT ACCOMMODATION (LAN) gene, in which Root-hair IT formation is strongly reduced, but intercellular rhizobial invasion eventually results in functional Nodule formation. LjLAN encodes a protein that is homologous to Arabidopsis MEDIATOR 2/29/32 possibly acting as a subunit of a Mediator complex, a multiprotein complex required for gene transcription. We also show that LjLAN acts in parallel with a signaling pathway including LjCYCLOPS. In addition, the lan mutation drastically reduces the colonization levels of AMF. Taken together, our data provide a new factor that has a common role in symbiont accommodation process during Root Nodule and AM symbiosis
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nitrate mediated control of Root Nodule symbiosis
Current Opinion in Plant Biology, 2018Co-Authors: Hanna Nishida, Takuya SuzakiAbstract:Nitrogen is an indispensable inorganic nutrient that is required by plants throughout their life. Root Nodule symbiosis (RNS) is an important strategy mainly adopted by legumes to enhance nitrogen acquisition, where several key processes required for the establishment of the symbiosis, are pleiotropically controlled by nitrate availability in soil. Although the autoregulation of nodulation (AON), a systemic long-range signaling, has been suggested to be implicated in nitrate-induced control of RNS, AON alone is insufficient to fully explain the pleiotropic regulation that is induced by nitrate. A recent elucidation of the function of a NIN-LIKE PROTEIN transcription factor has provided greater insights into the genetic mechanisms underlying nitrate-induced control of RNS in varying nitrate environments.
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genetic basis of cytokinin and auxin functions during Root Nodule development
Frontiers in Plant Science, 2013Co-Authors: Masayoshi Kawaguchi, Takuya Suzaki, Momoyo ItoAbstract:The phytohormones cytokinin and auxin are essential for the control of diverse aspects of cell proliferation and differentiation processes in plants. Although both phytohormones have been suggested to play key roles in the regulation of Root Nodule development, only recently, significant progress has been made in the elucidation of the molecular genetic basis of cytokinin action in the model leguminous species, Lotus japonicus and Medicago truncatula. Identification and functional analyses of the putative cytokinin receptors LOTUS HISTIDINE KINASE 1 and M. truncatula CYTOKININ RESPONSE 1 have brought a greater understanding of how activation of cytokinin signaling is crucial to the initiation of Nodule primordia. Recent studies have also started to shed light on the roles of auxin in the regulation of Nodule development. Here, we review the history and recent progress of research into the roles of cytokinin and auxin, and their possible interactions, in Nodule development.
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positive and negative regulation of cortical cell division during Root Nodule development in lotus japonicus is accompanied by auxin response
Development, 2012Co-Authors: Masayoshi Kawaguchi, Takuya Suzaki, Momoyo Ito, Yosuke Umehara, Koji Yano, Norio SuganumaAbstract:Nodulation is a form of de novo organogenesis that occurs mainly in legumes. During early Nodule development, the host plant Root is infected by rhizobia that induce dedifferentiation of some cortical cells, which then proliferate to form the symbiotic Root Nodule primordium. Two classic phytohormones, cytokinin and auxin, play essential roles in diverse aspects of cell proliferation and differentiation. Although recent genetic studies have established how activation of cytokinin signaling is crucial to the control of cortical cell differentiation, the physiological pathways through which auxin might act in Nodule development are poorly characterized. Here, we report the detailed patterns of auxin accumulation during Nodule development in Lotus japonicus. Our analyses showed that auxin predominantly accumulates in dividing cortical cells and that Nodule INCEPTION, a key transcription factor in Nodule development, positively regulates this accumulation. Additionally, we found that auxin accumulation is inhibited by a systemic negative regulatory mechanism termed autoregulation of nodulation (AON). Analysis of the constitutive activation of LjCLE-RS genes, which encode putative Root-derived signals that function in AON, in combination with the determination of auxin accumulation patterns in proliferating cortical cells, indicated that activation of LjCLE-RS genes blocks the progress of further cortical cell division, probably through controlling auxin accumulation. Our data provide evidence for the existence of a novel fine-tuning mechanism that controls Nodule development in a cortical cell stage-dependent manner.
